Sequestering of cell solutes from soluble to organized structures was investigated with regard to conformations of interacting molecules. Glycosaminoglycans and acid polysaccharides were characterized by optical properties. The ordered, negative charges specfically ordered amine cations and exhibited conformation-promoting effects on nonordered cationic polypeptides. Heparin (and other polyanions) with poly L-lysine: L-tyrosine promoted beta-structure, while with poly L-lysine: L-phenylalanine, alpha-helical order. That the nature of conformational change with heparin depended upon constellations of amino acids and their proclivity for alpha-helix or beta-structures bears on the molecular basis of granule formation, enzyme and antienzyme activation. Antithrombin (AT) activation depends upon an unique binding site in 15% of heparin (H) chains, having greater specific activity at 20,000 d than 6000 d. Present structure-function results with H fractions revealed unique conformation of sugars in the AT binding sequence and enhanced secondary structure in large active chains. A molecular model for H regulation of tyrosine hydroxylase (TH) analogous with H-AT led to discovery of inhibition by cationic peptides which increased Kapp tyrosine. H produced high Ki forms in preparation of TH in in vitro assays.